The Deformation and failure characteristics of rocks have been elucidated by uniaxial stiff tests and general triaxial tests. It is desirous to consider the post-failure properties of rocks on the design of underground excavations but few attempts have been carried out on it.
Firstly the authors have made a study of the formulation of failure criterion and post-failure behavior of rocks considering results of uniaxial compression, tension and triaxial compression tests. Secondly they have developed a method of elasto-plastic analysis of rock stress and deformation around underground excavations.
The applicability of this method has been investigated by comparing the results of analysis of the deformation around a circular tunnel with those of model experiments. It has been found that the elasto-plastic analysis gave better results than the conventional analyses, though the both did not show satisfactory accordance.
